Rock drill



July 19, 1927.

1,636,605 c. c. HANSEN ROCK DRILL Filed Sept. 25. 1926 IN VEN TOR.

' (in In (If men BY b H16 ATTO'R E Y Patented July 19, 1927.

UNITED STATES 1,636,605 PATENT OFFICE.

CHARLES C. HANSEN, O1! EASTON, PENNSYLVANIA, ASSIGNOB TO Bremen-nun COMPANY, 01 JERSEY CITY, NEW JERSEY, A CORPORATION OI rmw m.

BOOK DRILL.

Application fled September 28, 1926. Serial In. 188,547.

This invention relates to rock drills, but more particularly to a cooling device for cylinders and associated parts of fluid actuated rock drills of the hammer type.

The objects of'the invention are to prevent freezingvof the exhaust" ports of the cylinder, to insure thorough lubrication of the movable elements of the drill, and to obtain a cooling effect of the front end of the cylinder and associated arts.

Other objects will appear 7 ereinafter.

The invention is shown in one of its pre ferred forms in the accompanying drawin I in which igure 1 is a longitudinal sectional elevation of a rock drill having the invention applied thereto,

igure 2 is a transverse view taken through Figure 1 on the line 22, and

Figure 3 is a similar viewtaken through Figure 1 on the line 33. 7

Referring to the drawings in which is shown one embodiment which the invention may assume in practice, A designates a'cylinder closed in this instance at its rearward end by a back cylinder B. A front cylinder washer C forms a closure for the front end of the cylinder and is held securely in position by a front head D which extends into the front end of the cylinder A and forms a housing for a chuck E rotatable therein, the chuck E in this instance being interiorly threaded at its rearward end as at F to receive a. fluted chuck nut G.

The cylinder A is provided with a reciprocatory hammer piston H having a head J intermediate its ends. The piston H has a forward fluted extension K slidable through a bore L of the front cylinder washer C and interlocked in this instance with the chuck nut G for preventing relative rotation between the piston and the chuck parts.

The piston H is of the type which is constantly exposed at one end to live pressure fluid and has a rearward extension 0 reciprocable in a bore P of the back cylinder B. Within the rearward end of the extension 0 is disposed a fluted rifle nut Q which engages a rifle bar R in a well known manner for rotating the piston, together with the interlocking chuck parts during the rearward stroke of the piston.

In the present instance, the piston H is suitably bored to receive a water tube- S which may communicate at. its rearward end with a source of water supply (not shown) and extends with its front end into the rearward end of a hollow drill steel T in the front head D.

Pressure fluid may be conve ed to a passage U in the back cylinder B cm a source of supply by any suitable means and the admission of such pressure fluid to the rearward end of the bore P is controlled by a throttle valve V preferably-of the rotatable type. The distribution of such pressure fluid to the ends of the cylinder A is in this instance controlled by the rearward extension 0.

Leading from the rearward end of the bore P to a point near the forward end of said bore is a su' p l passage W for wnveying pressure n1 to the rearward end of the c linder. This passage is constantly supplie with ressure fluid and such ressure fluid -is a mitted to the rearw end of the cylinder shortly before the piston H reaches its rearwardmost limiting position. In this position of the iston, the front end of the passage W will be uncovered by'the extension 0 and pressure fluid will then flow around a neck X of the extension 0 and into the rearward end of the. cylinder to implel lt he piston forwardly against the drill stee The admission of ressure fluid to the front end of the cylin er is effected throu h a port Y communicatin with the bore at a point intermediate t e rearward end of said bore and the forward end of the passage W. This port Y opens into a longitudinal passage Z which in this instance parallels the cylinder bore and communicates at its front end with the front end of the cylinder throu h a port I).

In the type of rill illustrated, the pressure fluid utilized for im g the piston is cut off early in the stro e of the piston so 7 that the piston is actuated principally by the expansion of the pressure fluid. Certain ob'ectionable features obtain however in drllls of this type, particularly with respect to the freezing of the exhaust ports and with respect to heating of the front end of the cylinder and associated parts, such heat being caused by the compression generated by the piston on its forward stroke. The resent invention aims to eliminate these ob ectionable features, and to this end the fluid exend of t haustcd from thecylinder through an exhaust port 0 is conveyed through a passage d which communicates at its forward end with an internal annular groove e in the cylinder A adjacent the front cylinder washer C. An external annular groove f formed in the front cylinder washer C cooperates with the groove e to form a passage-way 2 around the front cylinder washer C, communication between the passage-way 2 and the atmosphere bein in this instance effected through an exhaust passage 9 in the cylinder'A, preferably situated diametricall opposite'to the point at which the pressure uid from the cylinder enters the passagewa 2. Y

n' order to at all times insure thorough lubrication of the piston extension K as well as the cooperating surfaces of the chuck parts, a plurality of passages h are formed in the front cylinder washer C. These passages communicate at one end-with the passage-way 2 and at the other end with the bore L lnsaid washer. In this way upon the exhaust of pressure fluid from the cylinder to the passage-Way 2, a portion of exhaust fluid together with entrained oil will pass through the front head and associated parts, thus assuring a uniform and suflicient supply of lubricant to those elements located forwardchannels described instead of exhausting directly to the atmosphere through a free exhaust port, the heat generated in the front e cylinder will be absorbed by the exhaust fluid and will increase the temperature of the exhaust fluid to such an extent that freezing of the exhaust passage 9 will be entirely eliminated.

As a result of this construction all parts of the drill will at all times remain sufficiently cool so that they may be readily handled without causing inconvenience to the operator.

Other advantageous features of the pres ent invention are that a uniform and adequate supply of lubricant may at all times be provided for the chuck parts and, since the lubricantis conveyed to these parts by fluid and the fluid so utilized in passing through the front head and chuck parts will prevent the admission of any dust or dirt into the front end of the drill.

I claim:

In a fluid actuated rock drill, the combination of a cylinder having an exhaust port, a hammer piston in the cylinder controlling the exhaust port, a fluted extension on the hammer piston, a front cylinder washer forming a closure for the front end of the cylinder and having a bore to slidably receive the extension, said front cylinder washer having an external annular groove, a passage in the cylinder to convey exhaust fluid from the exhaust port to the annular groove for cooling the front end of the cylinder, an exhaust passage in the cylinder for conveying such exhaust fluid from the annular groove to the atmosphere, and passages leading from the annular groove to the bore to convey pressure fluid and entrained In testimony whereof I have signed this specification.

CHARLES C. HANSEN. 

